Method and device for the continuous production of a thread by extrusion into a liquid

ABSTRACT

A method and device (1) for the continuous production of a thread (12) by extrusion of a molten material into a cooling liquid (9) applied by centrifuging against the inner wall (10) of a drum (11). The inner wall (10) of the drum (11) comprises a lateral surface (102) which progressively approaches the axis of rotation of the drum (11) in the direction towards the outside (E) of the drum (11). Means (23, 24) are used which make it possible to displace the thread (12) along said surface (102) so that the thread (12) emerges from the drum (11) under the action of the centrifugal force. Threads (12) obtained by this method and this device, these threads being, for instance, amorphous metal threads used to reinforce automobile tires.

BACKGROUND OF THE INVENTION

The present invention relates to methods and devices which make itpossible to obtain threads by casting in a liquid. Such threads are, forinstance, metal threads, particularly threads of amorphous alloys.

It is known to produce amorphous threads by projecting a jet of moltenalloy into a liquid cooling layer, for instance a layer of water,applied by centrifugal force against the inner wall of a rotary drum.Such methods are described, for instance, in U.S. Pat. Nos. 3,845,805,4,523,626 and French Patent 2 636 552. The Japanese Patent Applicationpublished under No. 63-137550 describes such a method in which use ismade of devices at the end of the drum in order to separate a givennumber of layers of threads. The thread is extracted upon the stoppingof the drum, so that this method cannot be used in continuous operation.

In order that a method of centrifugal casting in a drum can be used incontinuous operation, it is necessary to have the thread emerge from thedrum as it is formed. Various methods have been described for thispurpose. It has been proposed, for instance, to use magnetic devices inorder to apply the thread against a coil arranged outside the coolingliquid, these devices possibly furthermore employing a radially movinglever which is driven by the drum. Such methods are described, forinstance, in U.S. Pat. No. 4,617,983, in the Japanese Patent Applicationpublished under No. 62-89526, and in the international applicationpublished under No. WO 87/155. These devices are complicated to use andmay lead to instabilities of the film of water which are prejudicial tothe continuity of the thread. Water and thread evacuation devices havebeen described, for instance, in the Japanese Patent Applicationspublished under Nos. 60-61147, 60-76255, 60-166147, and 61-253147. Thesedevices are also complicated to use and, furthermore, they raise sealingproblems which are difficult to solve.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method and a devicewhich make it possible continuously to extract in simple manner a threadproduced by centrifuging in a drum without sealing problems arising. Themethod in accordance with the invention for the continuous production ofa solid thread by extrusion of a molten material into a cooling liquidapplied by centrifugal force against the inner wall of a drum ischaracterized by the following features:

a) a drum capable of rotating around an axis is used; the inner wall ofthe drum, which is in contact with the centrifuged liquid, has a lateralsurface which progressively approaches the axis of rotation in thedirection towards the outside of the drum;

b) means are used which make it possible to displace the thread alongsaid surface in such a manner that the thread then moves away from saidsurface, emerging from the drum under the action of the centrifugalforce.

The invention also concerns a device for the continuous obtaining of asolid thread by extrusion of a molten material into a cooling liquidapplied by centrifuging against the inner wall of a drum, the devicebeing characterized by the following features:

a) it comprises a drum and means making it possible to turn the drumaround an axis; the inner wall of the drum, intended to come intocontact with the centrifuged liquid, has a lateral surface whichprogressively approaches the axis of rotation in the direction towardsthe outside of the drum;

b) it comprises means making it possible to displace the thread alongsaid surface, said means being so arranged that the thread then movesaway from said surface, emerging from the drum under the action of thecentrifugal force.

The invention also concerns threads obtained by the method or devicepreviously described.

The invention also concerns articles reinforced with these threads, sucharticles being, for instance, belts, hoses or tires.

The invention will be easily understood by means of the followingnon-limitative examples and the diagrammatic figures relating to theseexamples.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a front view of a device according to the invention with adrum rotating around an axis, the view of FIG. 1 being taken in thedirection of the arrow F shown in FIG. 2;

FIG. 2 is a cross-sectional view of the device shown in FIG. 1, thissection being indicated by the line segments II in FIG. 1;

Each of FIGS. 3 and 4 shows, in greater detail, a part of the drum ofthe device shown in FIGS. 1 and 2, with a pusher, each of these figurescorresponding to one position of this pusher, these figures beingsections taken along planes passing through the axis of rotation of thedrum;

FIG. 5 shows, in front view, a part of this drum, this view being takenalong the arrow F shown in FIGS. 2 to 4;

FIG. 6 shows a part of the drum of another embodiment of the invention,along a section taken in a manner similar to FIGS. 3 and 4.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2 show a device in accordance with the invention for theproduction of amorphous metal threads. This device 1 comprises areservoir 2 formed of a crucible around which there is located theinduction coil 3 which makes it possible to melt the amorphizable metalalloy 4 having a base of iron which is contained within the reservoir 2.A gas 5 under pressure, for instance argon, makes it possible to causethe liquid alloy 4 to flow through the nozzle 6 so as to obtain a jet 7,this gas 5 being inert with respect to the alloy 4. This jet 7 arrivesat the layer 8 of cooling liquid 9 which is applied against the innerwall 10 of a drum 11, this liquid 9 being, for instance, water. The jet7 then solidifies very rapidly so as to form the amorphous metal thread12. The drum 11 turns around its axis in the direction of the arrow F₁₁,this axis being marked xx' in FIG. 2 and x in FIG. 1, and thecentrifugal force thus obtained applies the cooling liquid 9 in a layer8 against the inner wall 10. FIG. 1 is a front view, seen from theoutside of the drum, in the direction indicated by the arrow F in FIG.2, and FIG. 2 is a section taken in two planes, one of which passesthrough the axis xx' while the other is parallel to the axis xx', thissection being indicated by the straight line segments II in FIG. 1.

FIGS. 3, 4 and 5 each show in greater detail a part of the drum 11 withthe means in accordance with the invention for extracting the thread 12.FIGS. 3 and 4 are sections taken in a plane passing through the axisxx', FIG. 5 being a front view, seen from the outside of the drum, thisview being taken along the arrow F of FIGS. 2 to 4.

In FIGS. 3 and 4, the outside of the drum 11 is represented by theletter E. The drum 11 comprises a substantially flat plate 13perpendicular to the axis xx' and to which there is fastened a shaft 14driven by the motor 15 in order to drive the drum 11 in rotation aroundthe axis xx' (FIG. 2). The drum 11 comprises a plate 16 having thegeneral shape of a cylinder which revolves about the axis xx' and aplate 17, substantially parallel to the plate 13 and having the generalshape of a ring with axis xx', defining an opening 18 arranged on theside of the exterior E. The drum 11 furthermore comprises anintermediate plate 19 arranged between the plates 13 and 17, this plate19, which is perpendicular to the axis xx' and substantially parallel tothe plates 13 and 17, having substantially the shape of a ring with axisxx'. In the sectional views of FIGS. 3 and 4, the end 170 of the plate17 and the end 190 of the plate 19 are the closest to the axis xx' andboth of them are practically at the same distance from the axis xx'.

Upon the rotation of the drum 11, the plates 13, 17, 19 define two zones20, 21 in which the liquid 9 is present, the zone 20 being limited bythe plates 13, 16 and 19 and the zone 21, which is towards the outsideE, being limited by the plates 16, 17, 19. The thread 12 is formed inthe zone 21. The plate 19 is provided with openings 22 through each ofwhich a pusher 23 passes. A single one of these pushers is shown inFIGS. 3 and 4. This pusher 23 is formed of a rod having a linear part23A which is substantially parallel to the axis xx' and two linear ends23B, 23C parallel to each other and perpendicular to the part 23A, theseparts 23B, 23C being substantially disposed in a plane containing theaxis xx'. The part 23B is disposed in the-zone 20 and it is in contactwith a cam 24. The part 23C is disposed in the zone 21. The arrangementof all the pushers 23 is similar to the one which has just beendescribed, these pushers being distributed uniformly all around the drum11.

The inner wall 10 of the plate 16 is in contact with the liquid 9. Inthe zone 20, this inner wall, designated 100, has the shape of acylinder of revolution with axis xx'. In the zone 21, the inner wall 10has a surface, designated 101, in the vicinity of the plate 19 which hasthe shape of a cylinder of revolution with axis xx' and it has a lateralsurface 102, in the vicinity of the plate 17, which progressivelyapproaches the axis xx' in the direction towards the opening 18, that isto say, towards the outside E of the drum 11. This lateral surface 102has, for instance, the shape of a cone of axis xx', this cone flaringout in the direction of the plate 13. The liquid 9 is applied againstthe surfaces 100, 101, 102 by the centrifugal force upon the rotation ofthe drum 11.

In the sectional views of FIGS. 3 and 4, the surfaces 101, 102 are, forexample, linear and they form the angle α with each other (FIG. 3).

The thread 12 is formed in the zone 21 by cooling of the jet 7. Thecontact of the thread 12 with the wall 10 takes place on the surface 101at the point 25 (FIGS. 1 and 2). In order to facilitate the heatexchanges, the plates 13, 16, 17, 19 are, for instance, made of metal.

The pushers 23 initially have an arrangement such that their part 23C,in the zone 21, is arranged in the vicinity of the plate 19. Upon therotation of the drum 11, each pusher 23, which is driven in rotationwith the drum 11 and guided by the cam 24, is displaced towards thesurface 102, sliding in an opening 22 in the plate 19 and in grooves 26,27 made in the plate 16, in zones 20, 21, respectively. Upon thisdisplacement parallel to the axis xx', indicated diagrammatically by thearrow F₂₃ in FIG. 3, the end 23C of the pusher 23 comes into contactwith the thread 12 and pushes it on the surface 101 in order to bring itinto contact with the surface 102, whereupon this end 23C pushes thethread 12 towards the opening 18 so that this thread follows the lateralinclined surface 102. The thread 12 thus arrives at the opening 18 and,under the action of the centrifugal force, it emerges from the drum 11moving away from the lateral surface 102. The outer surface 17A of theplate 17 has, for instance, a conical shape in the vicinity of the end170, approaching the plate 13 when it approaches the axis xx' (FIGS. 3and 4), so as to facilitate this emergence. It is then possible tocollect the thread 12, for instance in order to wind it on a bobbin, thedevice 1 thus operating continuously. The means which permit the windingof the thread 12 outside the drum 11 have not been shown in the drawingfor purposes of simplification. The cam 24 then causes the return of thepusher 23 to its initial position, the end 23C being no longer incontact with the thread 12; this movement is indicated diagrammaticallyby the arrow F'₂₃ in FIG. 4 FIG. 3 shows a pusher 23 in its initialposition when its end 23C is in the vicinity of the plate 19, and FIG. 4shows the same pusher in its final position, that is to say when the end23C is furthest from the plate 19 and is in contact with or in thevicinity of the plate 17. The openings 22 and the grooves 26, 27 serveto guide the pushers 23 upon their above-described displacements, sothat their linear parts 23A remain substantially parallel to the axisxx' and their linear parts 23B, 23C remain substantially radial, that isto say substantially in a plane passing through the axis xx' for eachpusher, the number of these planes being equal to the number of thepushers 23, FIGS. 3 and 4 being taken along one such plane.

Each pusher 23 carries out a complete cycle (start from the initialposition and return to the initial position) during one rotation of thedrum 11, the cam 24 being so adapted that the action of the pushers 23on the thread 12 in order to cause it to emerge from the drum 11 takesplace after the point 25 in the direction of rotation of the drum. It isnot necessary for the position of contact of the pushers with the thread12 to be determined with any great precision. It is sufficient merelythat the thread 12 be ejected from the drum 11 before it has carried outa complete revolution in the drum. The device 1 can therefore operatewithout a device for the detecting of the point 25.

The role of the zone 20 is simply to avoid using sealing devices for theopenings 22 in which the pushers 23 slide, the liquid 9 passing withoutdisturbance from the zone 20 to the zone 21, or conversely, via theopenings 22. It is possible to dispense with the use of the zone 20 byproviding sealing packings for these openings 22 so as to avoid theemergence of the liquid 9 from the zone 21 while permitting the movementof the pushers 23, but this solution is more complicated that the onewhich has been described.

The invention therefore, in a very simple manner, permits continuousoperation of the device 1 without there being any sealing problem andwithout the use of magnetic devices or devices for detecting theposition of the thread 12.

EMBODIMENT

A thread of amorphous alloy is made in accordance with the inventionwith the device 1 employing the following conditions:

nature of the alloy 4: amorphizable alloy having a base of iron, nickel,silicon and boron, the composition of the alloy being approximately asfollows (atomic %): Fe: 38; Ni: 40; Si: 10; B: 12;

the weight of this alloy in the reservoir 2 is 100 grams;

the melting point of the alloy 4 is about 1050° C.; this molten alloy ismaintained at a temperature of 1100° C. in the reservoir 2;

characteristics of the device 1: inside diameter of the drum 11(diameter of the cylindrical part 101): 480 mm;

depth of the water in contact with the part 101: 14 mm;

value of α: 150°;

number of pushers 23: 60;

speed of rotation of the drum: 350 rpm;

temperature of the water 9: about 6° C.;

displacement of each pusher 23 along the axis xx' in the direction ofthe arrow F₂₃ : 35 mm.

Several hundred meters of a thread 12 of diameter 120 μm are producedcontinuously without a break in the thread; this thread having a rupturestrength of 2800 MPa and an elongation upon rupture of about 2%.

In the device 1, the pushers 23 were so arranged that their linear part23A is disposed in contact with the liquid 9 both in zones 20 and 21,the openings 22 being also in contact with this liquid.

FIG. 6 shows a portion of the drum 11 of another device 30 in accordancewith the invention, this FIG. 6 being a section taken in a mannersimilar to FIGS. 3 and 4. From this FIG. 6 it is seen that the pusher 31has a linear part 31A parallel to the axis xx' and two linear parts 31B,31C perpendicular to the part 31A and arranged substantially in a radialplane. The part 31A slides in the opening 32 of the intermediate plate19, in accordance with the opposite arrows F₃₁, F'₃₁, parallel to xx'.The opening 32 is not in contact with the liquid 9, the part 31B incontact with the cam 24 and the part 31A thus moving without being incontact with the liquid 9. Only the part 31C, intended to push thethread 12 on the surface 102 is in contact with the liquid 9. There istherefore no sealing problem between the zones 20, 21.

Moreover, the groove 26 becomes useless in the zone 20 and there istherefore only one groove 27 per pusher 31 in the zone 21, whichsimplifies the production. The zone 20 can thus be without liquid 9 ifdesired in order to limit the weight or it can contain liquid 9 whichthen serves as thermal flywheel. One can even eliminate the zone 20, theplate 19 constituting, for instance, the plate 13.

The invention is not limited to the production of amorphous metalthreads. It applies to the production of non-amorphous metal threads,for instance, microcrystalline threads, or to the production ofnonmetallic threads, for instance threads of inorganic or organicmaterial.

Of course, the invention is not limited to the embodiments which havebeen described above. Thus, for instance, the thread,-upon itsextrusion, can be placed in contact with the lateral surface whichprogressively approaches the axis of rotation, the inner wall of thedrum having, for instance, a generally conical shape without cylindricalpart. Furthermore, means other than the pushers described above can beused to displace the threads, and several cams can be used for eachdevice, or means other than cams can be used.

We claim:
 1. A method for the continuous production of a solid thread byextrusion of a molten material into a cooling liquid applied bycentrifuging against the inner wall of a drum comprising:(a) rotating adrum about an axis, the drum having an inner wall in contact with acentrifuged liquid, the inner wall comprising a lateral surface whichprogressively approaches the axis of rotation in a direction towards theoutside of the drum; (b) using means to displace the thread along saidsurface, so that the thread moves away from said surface emerging fromthe drum under the action of the centrifugal force.
 2. A methodaccording to claim 1, in which the means for the displacement of thethread comprise pushers.
 3. A method according to claim 2, includingactuating the pushers by at least one cam.
 4. A method according toclaim 2, in which the drum is separated into two zones by a plate andincluding sliding the pushers in openings of the plate.
 5. A methodaccording to claim 2, in which the drum is separated into two zonescontaining cooling liquid by a plate perpendicular to the axis of thedrum, said plate being provided with openings in which the pushersslide, one of these zones, directed towards the outside of the drum,being intended to receive the thread, and the liquid being able to passfrom one zone to the other through the openings.
 6. A method accordingto claim 1, including manufacturing a metal thread of amorphous alloy.7. A device for the continuous production of a solid thread by extrusionof a molten material into a cooling liquid comprising:(a) a drum andmeans for rotating the drum around an axis, the drum having an innerwall, intended to contact a centrifuged cooling liquid, the inner wallhaving a lateral surface which progressively approaches the axis ofrotation in the direction towards the outside of the drum; (b) means fordisplacing the thread along said surface, said means being so arrangedthat the thread then moves away from said surface emerging from the drumunder the action of centrifugal force.
 8. A device according to claim 7,in which the means for the displacement of the thread comprise pushers.9. A device according to claim 8, in which the means for thedisplacement of the thread comprise at least one cam for actuating thepushers.
 10. A device according to claim 8, including a plate providedwith openings in which the pushers slide.
 11. A device according toclaim 8, including a plate separating two zones of the drum in whichcooling liquid is contained, said plate being perpendicular to the axisof the drum and being provided with openings in which the pushers slide,one of said zones, directed towards the outside of the drum receivingthe thread, and the liquid being capable of passing from one zone to theother through the openings.
 12. A device according to claim 7 forproducing a metal thread of amorphous alloy.